Re: [PATCH v4 48/48] perf cpumap: Give CPUs their own type.

[Jiri Olsa]

On Tue, Jan 04, 2022 at 10:13:51PM -0800, Ian Rogers wrote:
> A common problem is confusing CPU map indices with the CPU, by wrapping
> the CPU with a struct then this is avoided. This approach is similar to
> atomic_t.
> 
> Suggested-by: John Garry <john.garry@xxxxxxxxxx>
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>

SNIP

>  tools/perf/util/stat.h                        |   2 +-
>  tools/perf/util/svghelper.c                   |   6 +-
>  tools/perf/util/synthetic-events.c            |  12 +-
>  tools/perf/util/synthetic-events.h            |   3 +-
>  tools/perf/util/util.h                        |   5 +-
>  59 files changed, 408 insertions(+), 347 deletions(-)

that's massive ;-) did it find any mis-use of the index/value?

how about the same for threads?

> diff --git a/tools/lib/perf/include/internal/cpumap.h b/tools/lib/perf/include/internal/cpumap.h
> index 71a31ed738c9..581f9ffb4237 100644
> --- a/tools/lib/perf/include/internal/cpumap.h
> +++ b/tools/lib/perf/include/internal/cpumap.h
> @@ -4,6 +4,11 @@
>  
>  #include <linux/refcount.h>
>  
> +/** A wrapper around a CPU to avoid confusion with the perf_cpu_map's map's indices. */
> +struct perf_cpu {
> +	int cpu;
> +};

should we use 'int val' or 'int v' instead, so we don't have cpu.cpu ?

jirka

SNIP